Jacketed wire layer removing tool

ABSTRACT

A tool for selectively removing layers from jacketed wire. The tool incorporates an anvil and cutting head on spring biased lever arms. The cutting head mounts spaced parallel circumferential slitting blades positioned over a first wire guide channel on the anvil and a longitudinal slitting blade positioned over a second wire guide channel on the anvil. The blades are adjustable to regulate the depth of cut. The circumferential slit is made by rotating the tool around the wire with the wire in the first guide channel and then placing the wire in the second guide channel to longitudinally slit and remove the layer over a length corresponding to the spacing between the circumferential slitting blades.

D United States Patent [191 Prince [451 Oct. 28, 1975 [76] Inventor: Jack Henry Prince, 3642 Knoxie,

San Diego, Calif. 92105 [22] Filed: Aug. 2, 1974 [21] Appl. No.: 494,286

Primary Examiner-Al Lawrence Smith Assistant ExaminerJ. T. Zatarga Attorney, Agent, or FirmBrown & Martin [57] ABSTRACT A tool for selectively removing layers from jacketed wire. The tool incorporates an anvil and cutting head on spring biased lever arms. The cutting head mounts spaced parallel circumferential slitting blades positioned over a first wire guide channel on the anvil and a longitudinal slitting blade positioned over a second wire guide channel on the anvil. The blades are adjustable to regulate the depth of cut. The circumferential slit is made by rotating the tool around the wire with the wire in the first guide channel and then placing the wire in the second guide channel to longitudinally slit and remove the layer over a length corresponding to the spacing between the circumferential slitting blades.

4 Claims, 8 Drawing Figures I6 mum US. Patent Oct. 28, 1975 JACKETED WIRE LAYER REMOVING TOOL BACKGROUND OF THE INVENTION Various wire stripping, trimming and cutting tools have been developed for the purpose of selectively removing layers from jacketed wire. Typical tasks performed by these tools are the removal of the outer insulative jacket either from the end of the wire or intermediate the ends of the wire to form a window, removal of the shield braid layer, and removal of the center conductor insulator. The available tools range from hand tools in the form of pliers with cutting blades that have a V-or circular shape so that they cut through a portion of the layered wire without cutting desired layers, to semi-automated and automated strippers with rotary cutting action. Among the most difficult tasks to be performed by such devices is the cutting of a window in coaxial cable. The window consists of a portion of the outer insulative jacket which is removed, over a portion of the length of the cable, to permit the use of a solder sleeve in making an electrical connection to the shield braid. Such a process requires cutting through the insulative jacket around the circumference of the wire at two spaced points and then removing the jacket by extending a slit between the circumferential cuts. No successful tools especially adapted to perform this task have been successfully developed. Industry practice has been to employ skilled workers utilizing hand held blade cutters which are manually manipulated to make the two circumferential cuts and to remove the jacketed layer between the circumferential cuts by a longitudinal slit. In such an operation the depth of cut is unregulated except by the operators ability and experience. Therefore, it is possible that the shield braid will be damaged in such an operation. Such shield braid damage is particularly critical where it may make it necessary to repair or discard an entire wiring harness containing a large number of shielded wires if a single one is defective. It is also possible that the damage to the shield will go undetected producing a defective harness that will malfunction in service. An additional deficiency with the conventional technique for forming windows is that the manually held blade is unprotected and the possibility of serious injury to the worker is significant.

The range of prior art devices available for dead ending shielded wire is considerably greater than that available for the production of windows noted above. The dead ending operation consists in part of cutting through the shield braid and at a spaced point cutting through the inner insulator to expose the center conductor. However, the prior art tools and mechanisms for this purpose are generally inflexible in their ablility to handle a large range of wire sizes without adjustment or to accomplish extended length longitudinal slitting of the outer jacket.

Accordingly, it is desirable to have a jacketed wire layer removing tool which is capable of removing the outer insulative jacket to form a window or to form an extended length of the wire over which the shield braid is exposed especially where such a tool is also capable of selectively stripping the shield braid and inner insu' lator and where the various cuts are made with minimum possibility of damage to the adjacent layers.

rates a cutting head mounted in opposition to an anvil. The cutting head and anvil are carried on first and second operating levers which are pivotally biased together through the use of a torsion spring with ex-- tended ends received over the respective operating levers between the pivot point around the spring and the head and anvil. The face of the anvil which is in opposition to the cutting head contains first and second longitudinal wire guide channels which extend transversly to the longitudinal axis of the operating levers and are sized to receive the range of wire sizes to which the particular tool is directed. A pair of circumferential slitting blades are mounted on the cutting head so that they may protrude beyond that face of the cutting head which is in opposition to the anvil. The circumferential slitting blades are mounted on opposite side faces of the cutting head so that they are spaced by a distance corresponding to the desired window length. The blade is positioned over the first wire guide channel on the anvil. A third blade is mounted on a perpendicularly related side face of the cutting head and is positioned over the second wire guide channel on the anvil, such that the blade is parallel with the second wire guide channel and extends over substantially the same length as exists between the circumferential slitting blades.

In use as a tool for cutting windows, the circumferential slitting blades are adjusted to protrude beyond the body of the cutting head by a distance equal to the depth of the insulative jacket. The longitudinal slitting blade is similarly set.

The circumferential slits for the window are made with a rotary action. The wire is placed in the first wire guide channel and the tool is rotated about the wire as an axis so that the circumferential slitting blades cut parallel circular paths in the jacket. The torsion spring provides a controlled close bias between the head and anvil so that a regulated pressure is applied to the blades to produce uniform cutting action. After the circumferential cuts are made the wire is moved to the second wire guide, and the longitudinal slitting blade is pressed into the insulative layer, with the aid of the close bias from the torsion spring, to produce a longitudinal slit that connects between the circumferential slits and thereby releases the jacket from the wire over the length of the window.

In use as a wire stripper and extended longitudinal slitting device, the circumferential slitting blades are adjusted such that one blade is retracted and the other blade is extended to cut at a depth equal to that of the desired layer to be removed. For example, in removing the shield braid and inner conductor, the circumferential slitting blade is adjusted to penetrate the wire into the immediate proximity of the center conductor. In this manner, when the tool is rotated about the wire, with the wire in the first wire guide channel, the circumferential slitting blade cuts through all of the layers of the wire down to the center conductor so that the undesired portion of the outer layers may be removed by withdrawing them over the end of the wire. For extended longitudinal stripping of the outer jacket, for example, a longitudinal slitting blade with a rounded cutting edge is substituted for the window slitting blade. The depth of cut is adjusted to correspond to the depth of the layer to be removed. The wire is placed in the second wire guide channel. Then the entire tool is drawn longitudinally along the wire producing a longitudinal slitting action over any desired length.

It is therefore an object of the invention to provide a new and improved jacketed wire layer removing tool.

It is another object of the invention to provide a new and improved jacketed wire layer removing tool that reduces the incidence of defective parts.

It is another object of the invention to provide a new and improved jacketed wire layer removing tool that may be utilized over a wide range of wire sizes without adjustment.

It is another object of the invention to provide a new and improved jacketed wire layer removing tool that will remove the insulative jacket over all commonly encountered insulative materials.

It is another object of the invention to provide a new and improved jacketed wire layer removing tool that reduces the production labor requirement, particularly for the production of windows in insulative jacket.

It is another object of the invention to provide a new and improved jacketed wire layer removing tool that requires a minimum of manual dexterity.

It is another object of the invention to provide a new and improved jacketed wire layer removing tool that performs all wire trimming operations.

It is another object of the invention to provide a new and improved jacketed wire layer removing tool that may be set for a precise depth of cut.

It is another object of the invention to provide a new and improved jacketed wire layer removing tool which reduces the likelyhood of operator injury.

Other objects and many attendant advantages of the invention will become more apparent upon a reading of the following detailed description together with the drawings in which like reference numerals refer to like parts throughout, and in which:

FIG. 1 is a perspective view of the tool with a wire positioned for circumferential slitting.

FIG. 2 is a partial top plan view of the tool.

FIG. 3 is an enlarged sectional view taken on line 33 of FIG. 2.

FIG. 4 is a similar sectional view, but with the wire in position for longitudinal slitting.

FIG. 5 is a sectional view taken on line 55 of FIG. 3.

FIG. 6 is a perspective view of a typical wire with the insulative jacket partially removed.

FIG. 7 is a sectional view similar to a portion of FIG. 5, showing the use of a gauge to set the blades.

FIG. 8 is an end elevation view of the tool with an alternative longitudinal slitting blade for extended longitudinal slitting.

Referring now to the drawings, there is illustrated the tool 10 comprising a cutting head 12 in opposition to anvil 14. The cutting head is connected to an operating lever 16 and the anvil connected to an operating lever 18. A torsion spring 20 with extended ends 54 and 58 forms an interconnection means to pivotally interconnect the operating levers for relative pivotal movement about the coil portion 52 of the torsion spring 20. The torsion spring 20 creates close bias tending to force the opposing faces of the cutting head and anvil into engagement. The terminal portions of the extended ends 54 and 58 on torsion spring 20 are received in slots 56 and 60 on the levers I6 and 18 respectively.

A pair of guide flanges 90 and 92 are secured to the operating lever 18 and extend upwardly to the immediate proximity of the sides of operating lever 16.

The cutting head 12 is configured with four operational faces. The first face mounts a circumferential slitting blade 22 in a planar slot 24. The blade position is adjustable by the mechanism of a lock-screw 26 so that the amount by which the blade protrudes beyond the second face 28 may be set. A third face of the cutting head mounts a longitudinal slitting blade 30 which is adjustable for the extent of its protrusion beyond the second face 28 by the mechanism of the lock-screw 34 which controls the vertical position of the blade 30 within the slot 32. The fourth face of the cutting head mounts a circumferential slitting blade 36 within a planar slot 38 for adjustment through the mechanism of the lock-screw 40. The anvil has an opposing face 45 which is in opposition to the second face 28 of the cutting head 12. Two wire guide channels 42 and 44 extend transversely across the face 45 of the anvil 14. The first wire guide channel 42 is positioned to be in opposition to and directly beneath the cutting blades 22 and 36 and the second wire guide channel 44 is positioned directly beneath the longitudinal slitting blade 30. Clearance for the circumferential slitting blades 22 and 36 is provided by longitudinal blade clearance channels 46 and 48. The anvil includes a bore extending in parallelism to the wire guide channels 42 and 44 for the purpose of receiving a measuring rod which is illustrated in phantom at the number 72.

Referring specifically to FIG. 8 there is illustrated an extended longitudinal slitting blade 31 including a rounded cutting edge contour 33.

OPERATION The invention will be more fully understood by description of its use in association with several wire trimming operatings. In FIG. 1, there is illustrated a jacketed wire in the form of coaxial cable 62. As more clearly appears in FIG. 6, the cable 62 comprises an outer insulative layer 64, which generally is of plastic material, over a braided metallic shield layer 66. An inner insulative layer 68 surrounds the center conductor 70. Referring to FIGS. 1 through 3 it will be noted that the circumferential slitting blades 22 and 36 have been adjusted so that they protrude beyond the second face 28 of the cutting head 12 by a distance which is substantially equal to the thickness of the insulative jacket 64. The wire 62 is placed within the wire guide channel 42 which holds the wire in longitudinal alignment under the clamping engagement pressure of the torsion spring 20. Circumferential slitting of the insulative jacket 64 is accomplished by rotating the tool 10 about the wire 62 as an axis of rotation for at least one revolution. The slitting blades penetrate the insulative layer in a complete circle such that the insulative layer is separated from the remainder of the insulation over the length of the wire referred to as a window. The circumferential slits made by the blades 22 and 36 are illustrated as the slits 63 and 65 in FIG. 6. Since the depth of the blades may be adjusted over infinite range of positions by the adjustment screws 26 and 40 it is possible to obtain the precise depth of cut which penetrates the insulative layer 64 but does not contact or cut the shield braid 66. The guide flanges and 92 restrain the side to side relative movement to insure that the blade makes a true circular track.

A longitudinal slit is required to remove the section of insulation 67. In the apparatus of the invention, this longitudinal slit is accomplished without additional tools, and without adjustment of the tool, by moving the wire 62 to the second wire guide channel 44. When positioned in the second wire guide channel, such as is illustrated in FIG. 2, the wire 62 is directly under the longitudinal slitting blade 30. For this application the longitudinal slitting blade has a straight cutting edge 91 of a length which corresponds to the distance between the parallel circumferential slitting blades 22 and 36. Thus when the tool is grasped between the thumb and index finger of the operator, and sufficient pressure is applied, the longitudinal slitting blade penetrates the insulative layer to sever the insulative layer along a line 69, such as is illustrated in FIG. 6. By a rocking action, the blade then causes insulative section 67 to be lifted away from the shielded braid so that it can be easily removed.

FIG. 8 illustrates the use of the extended longitudinal slitting blade 31 with its curved cutting edge 33. In some wire trimming operations it is desirable to remove an extended length of insulated outer layer or other layer of the wire. This is accomplished by a third mode of operation. The third mode utilizes the extended longitudinal slitting blade, and the outer wire guide channel 44, and in addition utilizes a longitudinal movement of the tool relative to the wire such that the longitudinal slitting blade produces a longitudinal cut through the outer insulative jacket for the desired length of the wire. Initial cuts for such an operation may be formed by retracting a single one of the first and second circumferential slitting blades and using the remaining blade to make circumferential slits and the start and terminus of the extended cut. It is also possible to utilize the tool of the invention for wire stripping operations, including the removal of the inner insulator 68. For these operations the blade 22 or 36 is extended a sufficient distance to cut through the outer layers but to remain out of contact with the center conductor 70. The wire is placed in position in the first wire guide channel under the circumferential slitting blade, and the device rotated about the wire as previously described.

Referring now to FIG. 7, the use of a height gauge 96 to set the depth of cut for the circumferential slitting blades 22 and 36 is illustrated. The gauge 96 has a portion 98 which extends above the body of the gauge 96 by a distance equal to the desired depth of cut for the circumferential slitting blades. In use, the lock screws 26 and 40 are loosened. Spring pressure is allowed to force the face 28 of the cutting head 12, into contact with the gauge extended portion 98. In this action the blades 22 and 36 are pressed by the main body portion 96 of the gauge and move vertically in the guide slots 24 and 38 so that the depth of cut is reduced to the desired amount.

Having described my invention, I now claim:

1. A tool for selectively removing layers from jacketed wire, comprising:

a cutting head mounting a first circumferential slitting blade on a first face thereof and protruding beyond a second face, and mounting a longitudinal slitting blade on a third face thereof and protruding beyond said second face,

a second circumferential slitting blade mounted on a fourth face of said head and protruding beyond said second face,

an anvil having at least two longitudinal wire guide channels in a first face thereof,

interconnection means mounting said second face of said cutting head and said first face of said anvil in opposed relationship and biasing said anvil and said cutting head toward one another,

said first and said second circumferential slitting blades being positioned over, and transversely of, a first of said wire guide channels, and said longitudinal slitting blade being positioned over and aligned with a second of said second wire guide channels,

said first and second circumferential slitting blades being parallel to one another and spaced from one another along said first wire guide channel,

a first operating lever extending from said cutting head,

a second operating lever extending from said anvil generally aligned with and in opposition to said first operating lever,

said interconnection means providing a pivot point between the ends of said levers,

guide flanges extending from one of said operating levers,

said guide flanges being spaced from said pivot point and extending along and in close proximity to the sides of the other of said operating levers limiting the relative movement of said operating levers to pivotal rotation,

said first and second circumferential slitting blades and said longitudinal slitting blade being adjustable toward and away from said anvil.

2. A tool according to claim 1, wherein:

said first and second circumferential slitting blades and said longitudinal slitting blades being positioned in blade guides comprising planar slots in said first, third and fourth cutting head faces,

said blades having a width substantially equal to the width of said planar slots.

3. A tool according to claim 1, wherein:

the length of the cutting edge of said longitudinal slitting blade along said second wire guide channel is substantially equal to the distance between said first and said second circumferential slitting blades.

4. A tool according to claim 1, wherein:

said longitudinal slitting blade has a straight cutting edge. 

1. A tool for selectively removing layers from jacketed wire, comprising: a cutting head mounting a first circumferential slitting blade on a first face thereof and protruding beyond a second face, and mounting a longitudinal slitting blade on a third face thereof and protruding beyond said second face, a second circumferential slitting blade mounted on a fourth face of said head and protruding beyond said second face, an anvil having at least two longitudinal wire guide channels in a first face thereof, interconnection means mounting said second face of said cutting head and said first face of said anvil in opposed relationship and biasing said anvil and said cutting head toward one another, said first and said second circumferential slitting blades being positioned over, and transversely of, a first of said wire guide channels, and said longitudinal slitting blade being positioned over and aligned with a second of said second wire guide channels, said first and second circumferential slitting blades being parallel to one another and spaced from one another along said first wire guide channel, a first operating lever extending from said cutting head, a second operating lever extending from said anvil generally aligned with and in opposition to said first operating lever, said interconnection means providing a pivot point between the ends of said levers, guide flanges extending from one of said operating levers, said guide flanges being spaced from said pivot point and extending along and in close proximity to the sides of the other of said operating levers limiting the relative movement of said operating levers to pivotal rotation, said first and second circumferential slitting blades and said longitudinal slitting blade being adjustable toward and away from said anvil.
 2. A tool according to claim 1, wherein: said first and second circumferential slitting blades and said longitudinal slitting blades being positioned in blade guideS comprising planar slots in said first, third and fourth cutting head faces, said blades having a width substantially equal to the width of said planar slots.
 3. A tool according to claim 1, wherein: the length of the cutting edge of said longitudinal slitting blade along said second wire guide channel is substantially equal to the distance between said first and said second circumferential slitting blades.
 4. A tool according to claim 1, wherein: said longitudinal slitting blade has a straight cutting edge. 